A Bottom-Up Approach to Task Scheduling on Distributed Memory Multiprocessors

This paper presents a new approach to statically schedule parallel programs modeled as Directed Acyclic Graphs (DAGs) on various distributed memory multi-processor topologies represented as processor graphs to reduce the overall execution time of the program. The scheduler factors in the processor topology, communication delays and delays due to channel conflicts for scheduling. Our scheme differs dramatically from existing schedulers in that tasks of the DAG are scheduled bottom up. Experimental results presentedfor message switched systems using the hypercube and torus topologies show the effectiveness of our scheme. Our scheme can also be adapted for other topologies and routing schemes such as wormhole routing and circuit switching.